Bit of 6502 assembler that clears the bottom bit of the memory at &3AC (ampersand signifies hexadecimal in BBC Basic). User event pointer is set to point to the assembler, and then *FX14,4 causes the code to be called every vsync.The point of this? It allows you to load locked files from cassette tapes.

WHY! Do I remember this stuff, and not something useful like latin? :)